Event Class Number Formats
Event class numbers follow one of five formats (A to E), depending on the number of event classes in the organization. The format of an event class number can be determined from its four high-order bits.
Format A can be used by large organizations (such as OSF or major DCE vendors) that need more than 16 bits for the class ID. This format allocates 7 bits to the set ID and 24 bits to the class ID. Format A event class numbers with zero (0) as its set ID are assigned to OSF. That is, all event class numbers used by OSF have a zero in the most significant byte.
Format B can be used by intermediate-sized organizations that need 8 to 16 bits for the class ID.
Format C can be used by small organizations that need less than 8 bits for the class ID.
Format D is not administered by OSF and can be used freely within the cell. These event class numbers cannot be unique across cells and should not be used by application servers that are installed in more than one cell.
Format E is reserved for future use.
The numbers with 110 in the most significant bits (that is, 0xC0000000 to 0xDFFFFFFF) are reserved to be used locally within a cell.
The event class number formats are illustrated in the following figure (class event Ids are labeled "event-id").
Event Class Number Formats
The cell administrator is responsible for administering and assigning local event class numbers and their names.